Abstract

NUNEZ, Lidia et al. Health risk assessments in greywater in Buenos Aires state, Argentina. Rev. Int. Contam. Ambient [online]. 2014, vol.30, n.4, pp.341-350. ISSN 0188-4999.

The wastewater generated from domestic activities such as laundry, dishwashing, and bathing, when is disposed separately from the toilet discharges, is defined as greywater. Nevertheless its differences with sewage or wastewater, the presence of pathogenic microorganisms, and consequently the risks of disease transmission, was demonstrated in graywaters. These domestic effluents are mostly released, in urban areas of Argentine, to open ditches designed to evacuate greywater directly into rivers. The resulting risk of this disposal for human health has not been adequately studied. The aim of this study was to assess the health risk using quantitative microbial risk analysis (QMRA) on samples of raw greywater before and after sedimentation and passage through septa of sand. Indicator microrganisms were detected in all samples, the highest counts were for total coliform bacteria. Salmonella spp. was present in 20 % of tested samples. The greatest risk of infection from a single exposure was obtained for an accidental intake of 0.01 to 0.1 g of greywater contaminated soil, where the probability of infection with E. coli was 7.4 >10^-2. Regarding the filtred greywater the risk for E. coli infection decreased from 7.4 > 10^-2 to 4.2 > 10^-5.

Keywords : greywater; health risk; QMRA.

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